The Lancet has a global look at physical activity and it's not pretty. Researchers find that inactivity, which numerous studies have linked to a whole host of diseases, is responsible for about 9 percent of premature deaths. That works out to 5.3 million of the 57 million premature deaths in 2008.

Worldwide, 31.1 percent of adults rank as physically inactive. (That's defined, by the way, as less than 30 minutes of moderate activity 5 days a week or 20 minutes of vigorous activity three times a week).

Rates of physical inactivity vary hugely across the world. Just 4.7 percent of Bangladeshi citizens are rated as inactive. Malta, meanwhile, has the highest rate of inactivity: 71.9 percent of its residents fit the definition.

Internationally, men tend to be more physically active than women. That's true here in the United States, too. Here's the map of physically inactive men:

And then one for women:

The Lancet does contemplate a few ways to tackle inactivity, such as policies that encourage walking or biking to work. China seems to be furthest along in that regard, with 46 percent of its residents ranked as "active" commuters (Switzerland, at the low end, has 2.5 percent).

"If all noncyclists in Denmark became cyclists, about 12,000 deaths linked to little physical activity would be prevented every year as a result of cycling activity," the researchers conclude. (The researchers note some small, albeit relevant, risks, as 30 Danish cyclists do die in traffic fatalities annually.)